1. Technical Field
The present invention relates to an image processing device and method. More particularly, the present invention relates to an image processing device and method for measuring the coordinates of a photographing device or an object by keeping track of a dynamic image of the object taken when the photographing device moves relative to the object.
2. Related Art
There is known a technique to measure the position of a photographing device by continuously photographing an object while the photographing device is moving relative to the object. When the photographing device is actually mounted on a moving body such as a car or held in a hand of a person for photographing, however, stable images cannot always be obtained because of the sway of the car or the person, twists and turns of the road, or bumps and potholes on the road surface. Thus, it is necessary to correct vertical sway, magnification, direction and tilt for each frame. On other hand, for the case where a stationary object is photographed with a stationary photographing device, there is disclosed a 3D (three dimensional) measurement technique to precisely and automatically search for corresponding points for measurement. (See Patent Document 1.)
[Patent Document 1] JP-A-2003-264852 (paragraphs [0018] to [0073], FIGS. 1 to 11, etc.)
In order to measure the 3D coordinates of a photographing device or an object based on moving images, it is necessary to find, on two or more frames of the moving image, feature points (this may be referred to as characteristic points) corresponding to each other, or identical points on the object (hereinafter referred to “corresponding feature points”) and to keep track of them. The photographing position or the 3D coordinates of the object are finally calculated from the corresponding feature points of a selected pair of images, or stereo images. A problem has been found with the calculation, however, that solutions with stable precision cannot be easily obtained if the photographing distance (magnification), photographing direction or baseline length of the stereo images changes.
Thus, it is required to provide a technique that can precisely measure the photographing position or posture of a photographing device or the coordinates of an object even for sequentially changing photographed images, such as moving images, by removing inappropriate photographed images, which might deteriorate the measurement precision of 3D measurements, by developing the technique to photograph a stationary object with a stationary photographing device described above for application to the case where one or both of them are mobile.
The objective of the present invention is to provide an image processing device and method that can precisely measure the photographing position or posture of a photographing device or the coordinates of an object based on sequentially changing photographed images, such as moving images.